Robin Wright stars as Mary Surratt in Robert Redford's The Conspirator.

But odds are most don't know the story that director Robert Redford tells in his new film, The Conspirator, opening Friday.

The conspirator of the title is not the assassin, actor and Confederate loyalist John Wilkes Booth: The conspirator is Mary Surratt (Robin Wright), the lone woman tried by the military tribunal for the murder and the first woman executed by the United States.

"I'm attracted to the little-known story beneath the story you think you know," says Redford, 74. "What's fascinating is it's a story nobody knows about, that's tied to an event that everyone knows about. But you can boil it down to a story about a mother's love and sacrifice for her son."

The Conspirator arrives on the 146th anniversary of Lincoln's death and the 150th anniversary of the start of the Civil War, so interest in that compelling era is even higher than usual. And military tribunals are in the news now, with the upcoming trials for accused 9/11 terrorists to be held at Guantanamo Bay.

Will the April anniversaries bring more attention to The Conspirator? Redford is hopeful. His latest directorial effort is a low-budget (less than $20 million) independent film, a gripping courtroom drama (always a popular genre), and the first film from a new production group, the American Film Company, dedicated to making accurate movies about American history.

"The history you don't know," Redford says. "I didn't know this story; I hope it will be seen as fresh and new for people."

Guilty or innocent?

The people who do know history — the ever-vigilant army of Lincoln scholars — are beginning to weigh in on what Redford and company have wrought and the verdict is ... well, not as bad as some had feared.

"I was quaking in my boots when I heard Redford was involved, because of his political activism," says Laurie Verge, director of the Surratt House Museum in Clinton, Md., about 15 miles outside Washington. (Surratt's family home played a role in the Lincoln assassination and is now a museum specializing in Lincoln assassination studies.) But Verge was pleasantly surprised. "He turned out to be more sympathetic (to Surratt) than even I am."

Was Surratt guilty or innocent of plotting with Booth to assassinate Lincoln? It's still debated. Redford doesn't know, and moviegoers can make up their own minds.

What the movie does show is how the shock of America's first presidential assassination could threaten the Constitution's promise of a fair trial. It shows what can happen when civilians are tried by the military for a civilian crime. It shows the difference between a speedy trial and a rush to judgment, and how antiquated ideas about women can affect the dispensing of justice.

And it shows how the perception of unfairness can undermine for posterity even a valid verdict.

Historian Kate Clifford Larson of Simmons College in Boston, author of The Assassin's Accomplice: Mary Surratt and the Plot to Kill Abraham Lincoln, thought Surratt was innocent until her research convinced her otherwise. But she approves of The Conspirator. "Mary was a smart woman who made choices, and she paid for those choices," Larson says. "But her trial was a travesty."

Still, most Americans know nothing about it. How can it be that we don't have the full picture of the Lincoln assassination, one of the most shattering events in U.S. history? Redford says the government wanted it that way. In the movie, Secretary of War Edwin Stanton (Kevin Kline) makes clear what he wants to happen to those accused of killing Lincoln: "I want these people buried and forgotten," he shouts.

It seems to have worked.

"Americans are ignorant about our own history," says Fred Borch III, a retired Army colonel, former chief prosecutor at the Guantanamo military tribunals and a consulting historian on the movie. "If it didn't happen in the last 50 years, we just don't seem to be very interested — people can't even tell you who we were fighting in World War II."

It's puzzling because the full story is so much more compelling, says scriptwriter James Solomon, who started writing and research in 1993. "People look for conspiracies even where they may not exist. The Lincoln assassination is a remarkable conspiracy, and yet few know about it."

Instead, they know the basics: It is April 1865, just after the surrender of Confederate Gen. Robert E. Lee and the beginning of the end of four years of Civil War slaughter. The victorious president, having saved the union, goes to Ford's Theatre in Washington on April 14 to relax and see a play and is cut down in the presidential box by Booth, who escapes. Lincoln is taken to a house across the street, where he dies from a gunshot wound to the head early on April 15. Within days, Booth is tracked down and killed. End of story.

But actually, within weeks, eight other people are arrested, tried by a military commission (or tribunal), and convicted of a conspiracy that originally involved kidnapping Lincoln and holding him for ransom, and later escalated to a plot to kill him, his secretary of State, William Seward (who survived), and his vice president, Andrew Johnson (who succeeded Lincoln).

Who was Mary Surratt?

Surratt, 43, a Confederate sympathizer, widow and mother of three, ran the boardinghouse in Washington (now a Chinese restaurant), where her friend Booth and his co-conspirators, including her son, Confederate courier John Surratt, planned their harebrained schemes to decapitate the American government and somehow rescue the lost Confederate cause.

It's hard to overstate the shock after the assassination. Washington was in a panic, especially Stanton, who was convinced the Confederate leadership was behind the murder.

"Stanton was scared to death that the unity of the country, which was tenuous at best at the time, would fall apart, the South would resurge, and he was in a panic to get order quickly," Redford says.

This is a part of the story rarely told, Solomon says. "There are still armies in the field, there's a real feeling that the war is not yet won," he says. "Very few people understand the context — the fear, anxiety and terror are real."

Governments and people, when they're angry and terrified, can overreach, Borch says. "The parallels to today are obvious," he says.

But they are not exact. The trial took place in Washington and in public with reporters present, while the Guantanamo tribunals are taking place at an isolated base on Cuba. Also, the Gitmo tribunals have been anything but rushed, whereas the assassination trial was swift, and not pretty: There were no women on the jury (women could not even vote); the accused had no right to testify in their own behalf. There was no right to appeal. The military commission deliberated one day.Even though some on the commission recommended leniency for Surratt because of her age and gender, Stanton was opposed, and President Johnson signed the execution order.

Two days later, on the afternoon of July 7, Surratt was one of four of the convicted conspirators who were marched past four open graves, tied up and hooded, and then hanged on a scaffold at the Washington Arsenal Penitentiary, now part of Fort McNair.

About 150 civilians with tickets witnessed the execution; hundreds more gathered outside in a carnival-like atmosphere. Surratt's daughter Anna (Evan Rachel Wood) collapsed and was taken away.

For Redford and Solomon, The Conspirator isn't about parallels to modern events. After all, Solomon started writing the story eight years before 9/11.

They say it's a story about human relationships, especially the one between Surratt and her 28-year-old attorney, Frederick Aiken (James McAvoy), a Union soldier turned reluctant defender who came to sympathize with his Confederate client. And it's about Surratt and her son John (Johnny Simmons), who fled the country and left his mother to hang. (Two years later, unrepentant, he was tried in civilian court on the same conspiracy charges and got off after a mistrial.)

"To make an historic event resonate with the present, the story requires the human-relatable connective tissue of difficult choices and drama and interaction between people," Solomon says.

Says Larson: "It's a very human story, it makes historical characters people we can recognize."

Not every Lincoln scholar thinks The Conspirator is the whole truth and nothing but the truth — no two-hour Hollywood historical drama ever is — but even those who are exasperated with some of the details — where is Stanton's famously long, scraggly beard? — say they nevertheless like the movie.

"It's beautifully photographed, it evoked the period, the execution scene is so frightening and brilliantly conceived," says renowned Lincoln scholar Harold Holzer. "But (Redford) is presenting the idea that she was railroaded, which serious historians of the period know is not the case."

The question has long been pondered: Is it a good idea for Americans to get their history from the movies? Not, say Larson and Holzer, if they're learning the only thing they know about the Civil War from, say, fiction like Gone With the Wind.

"I might have tweaked a few things (about The Conspirator), but I'm not a filmmaker," Larson says. "It will create good conversations, which would be my goal as a teacher."

Redford hopes it will end up being shown in schools. "It belongs there because it shows a side of American history that is more complicated than most, and we are a complicated country."

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